The invention relates to removing condensate from air conditioning systems as well as other systems or devices that collect condensation.
Air conditioning systems generally include a blower which blows or draws air over a heat exchanger coil on which condensation accumulates and drips to a discharge pan positioned below the coil. The condensation (or condensate) which overflows from the pan is drained from the system through a discharge port on to the ground or into the sewer system.
Referring to FIG. 1A, an air conditioning system 10 includes a blower 11 positioned to draw external air through a filter 14 and push the air over a heat exchanger 12, thereby presenting positive pressure at the discharge port where the condensate is discharged. A system having the blower positioned with respect to the heat exchanger in this manner is known as a xe2x80x9cblow-throughxe2x80x9d system. Condensate from the heat exchanger drips into a condensate pan 13 having a drain port 15 connected to a U-shaped condensate trap 16.
Referring to FIG. 1B, on the other hand, if the blower is positioned to draw air over the coil, the system is a xe2x80x9cdraw-throughxe2x80x9d system with a negative pressure present at the port where the condensate is discharged. With this arrangement, blower 11 is positioned to pull air through the heat exchanger.
A condensate trap 16 in the form of U-shaped piping is generally provided at the discharge port. In a draw-through type system, the U-shaped trap 16 must be filled with water prior to starting up the system. In this case, the water serves as a barrier and is necessary in preventing the condensate pan from overflowing when the system is initially started up. In a blow-through type system, there is no requirement for xe2x80x9cprimingxe2x80x9d the system because condensation will accumulate during operation. In either case, the water in the trap forms a barrier between atmospheric pressure at the discharge port of the trap and the pressure level within the system, thereby preventing escape of conditioned air in the system of FIG. 1A or introducing air into the system of FIG. 1B. The trap also collects foreign material (e.g., sediment) passed through the discharge pan from the system. This foreign material can collect in the bottom of the trap and clog the system.
The invention is related to a condensate trap for use with an air conditioning system allowing trapped condensate and foreign material collected in the trap to be safely removed from the system.
In a general aspect of the invention, the condensate trap for an air conditioning system includes a chamber having an upstream port for coupling to the air conditioning system and a downstream port open to the external atmosphere, a sealing device disposed in the chamber, an upper seat member disposed between the sealing device and upstream port, and a lower seat member whose upper surface is adapted to receive a biasing member which is disposed between the sealing device and the lower seat member. The biasing member maintains the sealing device in biased contact with the upper seat member to prevent the egress or ingress of air from or into the air conditioning system. Moreover, in response to a predetermined amount of condensation fluid accumulating in the chamber, the sealing device moves out of contact with the upper seat member to allow the fluid to drain from the downstream port of the chamber.
Embodiments of this aspect of the invention may include one or more of the following features. The biasing member is a spring, or a tube or rod made from rubber or other resilient material. The sealing device is a float, for example, a round and hollow ball. The chamber is formed as a cylindrical pipe. The upper seat member includes a gasket seated in upper seat member. The lower seat member also includes a gasket seated in lower seat member, the gasket having an upper surface adapted to support the biasing member. The cylindrical pipe is formed of a transparent material to allow the installation or service technician to visually inspect and ensure that the condensate trap is properly operating.
Among other advantages of the invention, infiltration of air into and out of the system is minimized, thereby reducing pressure imbalances within the building. Preventing transfer of air between the air conditioning system and external atmosphere is achieved by the trap whether the system is used with a draw-through or blow-through system. For example, when used with a draw-through system, the trap prevents air from the external atmosphere (which may be polluted) from infiltrating the system. When used with a blow-through system, the trap prevents loss of air from the air conditioning system to the external atmosphere. In either case, the trap also prevents collected condensate or other foreign matter (e.g., sediment) from accumulating in the trap. The trap is configured to allow the condensate and foreign matter to drain from the system through the bottom of the trap. Thus, unlike conventional U-traps, sediment which can clog the trap does not accumulate in the trap. Moreover, the trap isolates the air conditioning system from the external atmosphere, without requiring the use of fluid (e.g., collected condensate) which is required in conventional U-piping traps. Thus, in the present invention, there is no risk of damaging the trap due to freezing of the fluid in the trap.
The condensate trap is compact, easy to install, and is easily removed from the system for maintenance or repair. The trap can be installed at virtually any point along the length of the drain pipe. For example, the trap can be installed at the end of an outdoor drain pipe and should be accessible for cleaning. In humid environments (e.g., regions of the southern United States) certain types of algae can grow on and within the trap. In such environments, it may be advantageous to have the trap outside where ultraviolet light will help prevent the growth of algae. The trap can also be directly substituted for a conventional U-piping trap without requiring any modification to the existing air conditioning or duct system. The spring is made from a non-corrosive material, such as stainless steel, and the length or other dimension of the spring can be changed to match requirements of different systems. Other features and advantages directed to the construction and materials of the condensate trap 20 are discussed in U.S. Pat. No. 5,644,925, which is incorporated herein by reference.
Other features and advantages of the invention will become apparent from the following detailed description, and from the claims.